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BUG: KASAN: slab-use-after-free in kobject_uevent_net_broadcast+0x110/0x53c lib/kobject_uevent.c:415
Read of size 8 at addr ffff0000d1f57290 by task syz.4.454/7984

CPU: 0 UID: 0 PID: 7984 Comm: syz.4.454 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/23/2026
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xb0/0x238 mm/kasan/report.c:378
 print_report+0x68/0x84 mm/kasan/report.c:482
 kasan_report+0x8c/0xc4 mm/kasan/report.c:595
 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381
 kobject_uevent_net_broadcast+0x110/0x53c lib/kobject_uevent.c:415
 kobject_uevent_env+0x518/0x944 lib/kobject_uevent.c:611
 kobject_uevent+0x2c/0x3c lib/kobject_uevent.c:659
 device_del+0x5f8/0x71c drivers/base/core.c:3983
 remove_one_compat_dev+0x5c/0x7c drivers/infiniband/core/device.c:1036
 remove_compat_devs drivers/infiniband/core/device.c:1047 [inline]
 disable_device+0x184/0x240 drivers/infiniband/core/device.c:1339
 __ib_unregister_device+0x214/0x33c drivers/infiniband/core/device.c:1571
 ib_unregister_device_and_put+0x5c/0x80 drivers/infiniband/core/device.c:1636
 nldev_dellink+0x330/0x374 drivers/infiniband/core/nldev.c:1902
 rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:-1 [inline]
 rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
 rdma_nl_rcv+0x4f0/0x814 drivers/infiniband/core/netlink.c:259
 netlink_unicast_kernel net/netlink/af_netlink.c:1338 [inline]
 netlink_unicast+0x600/0x7f8 net/netlink/af_netlink.c:1364
 netlink_sendmsg+0x648/0x948 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:800 [inline]
 __sock_sendmsg+0xc8/0x17c net/socket.c:815
 ____sys_sendmsg+0x3d0/0x6c8 net/socket.c:2713
 ___sys_sendmsg+0x198/0x224 net/socket.c:2767
 __sys_sendmsg+0x158/0x204 net/socket.c:2799
 __do_sys_sendmsg net/socket.c:2804 [inline]
 __se_sys_sendmsg net/socket.c:2802 [inline]
 __arm64_sys_sendmsg+0x88/0x9c net/socket.c:2802
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606

Allocated by task 7820:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:78
 kasan_save_alloc_info+0x40/0x50 mm/kasan/generic.c:570
 poison_kmalloc_redzone mm/kasan/common.c:409 [inline]
 __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:426
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x2f4/0x5fc mm/slub.c:5563
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 uevent_net_init+0xcc/0x2a0 lib/kobject_uevent.c:782
 ops_init+0x2cc/0x528 net/core/net_namespace.c:137
 setup_net+0x118/0x2fc net/core/net_namespace.c:443
 copy_net_ns+0x454/0x698 net/core/net_namespace.c:582
 create_new_namespaces+0x304/0x50c kernel/nsproxy.c:132
 unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:234
 ksys_unshare+0x438/0x6e0 kernel/fork.c:3297
 __do_sys_unshare kernel/fork.c:3365 [inline]
 __se_sys_unshare kernel/fork.c:3363 [inline]
 __arm64_sys_unshare+0x40/0x54 kernel/fork.c:3363
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x19c/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606

Freed by task 40:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:78
 kasan_save_free_info+0x54/0x6c mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:264 [inline]
 __kasan_slab_free+0x74/0xa4 mm/kasan/common.c:296
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2748 [inline]
 slab_free mm/slub.c:6509 [inline]
 kfree+0x188/0x658 mm/slub.c:6802
 uevent_net_exit+0x1b0/0x1cc lib/kobject_uevent.c:816
 ops_exit_list net/core/net_namespace.c:200 [inline]
 ops_undo_list+0x3cc/0x81c net/core/net_namespace.c:253
 cleanup_net+0x474/0x6c4 net/core/net_namespace.c:706
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x91c/0x1250 kernel/workqueue.c:3479
 worker_thread+0x798/0xbd0 kernel/workqueue.c:3560
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854

The buggy address belongs to the object at ffff0000d1f57280
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 16 bytes inside of
 freed 32-byte region [ffff0000d1f57280, ffff0000d1f572a0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x111f57
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 05ffc00000000000 ffff0000c0001780 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000400040 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d1f57180: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
 ffff0000d1f57200: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff0000d1f57280: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
                         ^
 ffff0000d1f57300: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
 ffff0000d1f57380: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
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